Gas carburetor



R. F. ENSIGN GAS CARBURETOR April 25, 1939.

Filed April 10, 1934 Even/qr. Roy. E Erzsyru.

Patented Apr. 25, 1939 UNITED STATES GAS cAnBURE'ro'n Roy F. Ensign, SanMarino, CaliL, assignor to Ensign Carburetor 00., Ltd., Huntington Park,Calif., a corporation of California Application April 10, 1934, SerialNo. 719,872 '15 Claims. (01. 48-180) This invention relates to gascarburetors; and one of the general objects of the invention is toprovide a carburetor so constituted and so functioning that it will becapable of operating when supplied with gas at a normal pressureglessthan atmospheric; or less than that at which the carburetor is suppliedwith air. And it is a general object of the invention to provide asimple mechanism which will accurately proportion the fuel throughoutthe range of operation and automatically stop the flow of gas wheneverthe engine stops operation.

In Patent No. 2,073,299, granted March 9, 1937, on Gas carburetingapparatus, I have described a carburetor and gas regulator apparatus ofsomewhat difierent type and which in general accomplishes the sameobjects; and in certain broad features the arrangement shown in thispresent application is similar to that of my prior application. In otherparticular features, however, and particularly with regard to thearrangement for automatically causing gas flow when the engine is inoperation, the present invention provides a difierent specific structureand action for accomplishing the same general purposes. There are alsocertain novel features in connection with the economizer control whichwill be explained hereinafter.

30 One of the difliculties encountered in the operation of anycarburetor on gas at low pressure lies in the fact-that the motor willnot idle at low speeds because the venturi, when large enough toaccommodate the air flow for maxi- 35 mum power, is too large to createa sufficient suction at low speeds to draw the required amount of gasfrom a regulator which has been set to deliver at sufiiciently belowatmosphere to insure that its valve will close when the suction 40 onitlgi, outlet ceases. Another difficulty is that the gas pressure at thecarburetor gas intake usually varies one hundred per cent or morebecause of the varying inlet pressures on the regulator. Whileregulators are known which 45 will deliver a substantially uniformpressure with varying iinitial pressures, the average regulator in'usedoes not do that, and delivers a varying regulated pressure on accountof the varying initial pressure in gas mains, or the varying pres- 50sures obtainable from the very commonly used tanks of liquid petroleumgasjin which the pressures vary ,greatly with temperature changes. Suchchanges in the gas pressure supplied to the carburetor make it verydifficult to maintain 55 a combustible mixture ratioproperly through vthe operating ranges of the engine, and particularly at low speed idlingoperation.

The present invention overcomes such difilculties by providingan'automatic proportioning means in-connection with the venturi, whichwill 5 cause the provision of the proper mixture for starting, andidling at low speeds, and for oper-v ation through the other operatingranges, regardless of the varying sub-atmospheric pressure of the gassupply. This is done by so placing a floating air valve that it forms ayielding obstruction in the air flow to the venturi. By utilizing adiaphragm tending to close the floating air valve, and by applying tothat diaphragm u the pressure of the gas supplied to the carburetor,

a balance of forces is set up which insures atall times a properproportioning of the air and the gas supply.

A carburetor in'typical and illustrative embodiment of the presentinvention, and in association with the gas regulator typical of any gasregulator, but having certain special features hereinafter described, isshown in the accompanying drawing, in which:

Fig. 1 is a view, predominantly in central vertical section,illustrating the carburetor and its association with the regulator;

' Fig. 2 is-a detail cross section of the carburetor taken on line 2-2of Fig. 1; and I Fig. 3 is a detail cross section of the carburetortaken on line 3-3 of Fig. 1;

The carburetor here illustrated has a suction passage generallyindicated by the numeral l0, containing the usual throttle II, a venturiI2 and anair'. inlet Hi, the upper end of the suction passage beingadapted to connect with the engine manifold (not shown). These featuresare all typical; their particular design is of no moment in myinvention, and the venturi may be substituted by any device whichcreates a fuel inspiring depression by reason of air velocity. Formed inthe carburetor casting are gas inlets l4 and I5, one of which, I5, iscontrolled by the adjustment needle Hi; the other two of which M, arethreaded and may be plugged, as indicated at Ma, for larger adjustment.controls of the gas inlet, depending upon the B. t.- u. content of thegas being used. These gas inlets are shown as fed by the pipe connection,l! which leads from the outlet of regulator R; and the inlets feed intoa substantially annular passage l8 that surrounds the venturi. Theventuri has at its throat the gas inlet orifices l9.

, The economizer arrangement includes a balance passage 26 communicatingwith air inlet l3 through, a calibrated bore 2|. In the constructionas-here shown a screw plug 22 holds throttle controlled suction in themain suction passage below the throttle.

A sliding valve 21 occupies valve bore 25, this valve having a hollowinterior 28 which, v'ia port 29, is always in communication with port26. A light spring 21a holds the valve normally in the position shown inFig. 3, and in this position passages 20 and 24 are in opencommunication with port 26. Valve bore 25 extends to the right ofpassage 24, as illustrated at 250; so that when valve 21 is moved overto the right in Fig. 3 it gradually and then finally cuts offcommunication of passages 26 and 24 with port 26.

Valve 21 has a projecting stein 36 which is engaged by lug 3| mounted onthrottle shaft 32, when the throttle is moved toward and to wide openposition. Thus, as the throttle approaches and then finally reaches wideopen position, valve 21 is moved to cut off communication of port 26with passages 24 and 20. 7

Leading off from passages 20 and 24 is a tube 35 that goes to the upperchamber 36 of regulator R, above its diaphragm 31. Passage 28 and theinterconnecting pipe 35 form a balance connection between the air intakeof the carburetor and a the reference pressure chamber ofregulator R.

idling operation when the depression (the amount by which the pressureis below atmospheric) is slight, the economizermay have little influence'upon the reference pressure placed upon the regulator diaphragm. Inorder to prevent that slight depression from drawing air from thebalance passage, spring seated :valve 26a may be inserted in passage 26;the spring 26b being strong enough to keep the valve seated againstslight epressions but allowing the valve to open when the depression inthe suction passage grows greater as medium running ranges areappreached. But as the throttle H opens'increasing the depression in thesuction passagebelowthe throttle, an increasing depression is placedupon the balance passage from port 26 the effect of that depression inlowering the pressure in connection 35 being modified .by the inflow ofair at the calibrated orifice 2 I. Then, as the throttle comes to fullopen position, movement of valve 21 cuts off the depression from port26, so as again to put full intake pressure on the regulator diaphragm.

In the regulator here illustrated it will be noted that increase of thereference, pressure in chamber 36 tends to lower the diaphragm and toopen the pressure controlling valve 40. The spring 4|,

adjustable in pressure by the regulation of plug 42, or by substitutionof other springs, tends to close valve 40. This spring also, through themedium of the interconnecting arm 4211. supports the weight of diaphragm31 and the interconnected parts. In normal operation spring 4| will beso set as to cause valve 40 to close surely and tightly .whenatmospheric pressure is present in the regulator outlet; the outletbeing connected via passage 43 with chamber 44 under diaphragm 31.Assuming that operation of the engine now applies suction to the outlet,pressure in chamber 44 is reduced, and the reference pressure in chamber36 above the diaphragm opens the regulator valve 46. Under theseconditions, variation in the reference pressure in chamber 36 will varythe pressure of gas delivery at the regulator outlet; and the action ofthe economizer in lowering the reference pressurethroughout the mediumof running ranges of the engine (throughout medium throttle positions)will cause valve 40 relatively to close andthus relatively to decreasethe delivery pressure of the outlet, and thus relatively to thin themixture formed by the carburetor throughout medium operating ranges. Asnoted, this action of the economizer is slight at closed position of thethrottle, so that the economizer In the lower part of the mainsuctionpassage there is a valve seat 50, and above it is a flare 5| in thepassage wall; so that the valve 52 which seats downwardly, or nearlyseats, on seat 50,

can rise into the flared part of the passage, and thus increase,proportionately as it rises, the air passage around the valve. In itsuppermost position, shown in dotted-lines in Fig. 1, the valve strikesthe stop pin 53 at its position of widest opening.

A valve stem 54 carries valve 52 and slides vertically in the stem guide55. The lower end of stem 54 rests on the head 56 of the bolt thatsecures the two plates 51 to diaphragm 58. Diaphragm 58 has above itchamber 59 in constant communication with the intake air pressure .viaport 66; and below it the diaphragm has a chamber 6| which is inconstant communication with the gas pressure at the carburetor inlet,via passage 62, tube 63, and port 64. The spring 65 supports diaphragm58, the supporting pressure of the spring being adjustable by means ofthe adjusting screw 66. Spring 65 is in practice so adjusted that itpractically balances the weight of the valve and the weight of thediaphragm, leaving only a suflicient unbalanced downward force that thevalve will return to its normal lowermost position, seating or almostseating on valve seat 50, when the motor is not in operation. When themotor is cranked for starting, the

valve 52 rises and, assisted by the spring pressed diaphragm 56, floatson the air stream, and by checking the air stream reduces the pressurein the suction passage above the valve. This reduced pressure will ofcourse be immediately communicated to the gas intake of the carburetorand thence, via port 64, connecting tube 63 and main passage; resultingin an increased depression in the passage above the valve, and againresulting in further downward movement of diaphragm 58'. The cycle ofactions is thus cumulative; so that very quickly after the motor startsto turn over the pressure in the carburetor gas inlet will be reducedto-the pressure at or below that at which the regulator discharges. Assoon as this condition has been reached, the regulatorvalve opens tofeed in gas 'to' maintain the pressure at the carburetor inlet at anequilibrium point. The carburetor then begins to take gas through theVenturi ports, and the floating valve 52 continues to play its part inmaintaining, at the Venturi throat, even during idling operation, thereduced pressure which is essential to drawing the gas into the throat.Immediately upon receiving the mixture the engine starts. During thiscondition of operation, at or near idling, valve 204 in the passage 20prevents the depression above valve 52 from being passed on to thebalance system and the regulator, where it would undesirably tend toaffect the regulator action to lower the delivered gas pressure duringidling.

As the throttle is opened to increase the-flow through the carburetor,valve 52 rises. So long as the engine is operating at idling or at lowspeeds, diaphragm 58 follows the valve upwardly; so that at all lowspeeds the valve is under the diaphragm control described. However, asthe speed phragm, floating on the air current, until the air' valvestrikes the limiting stop 53, which it does at moderate air velocitiesthrough the carburetor; and in this position it remains throughout thehigher operating ranges. The upward movement of diaphragm 58 is limited,in this particular design, by the bolt head 56 striking the upper wallof the diaphragm chamber. The valve and stem must of course besufficiently heavy to put the required restriction on the air stream toreduce the pressure as described. I find that the valve may be wellmade'of aluminum, the valve stem of steel; and the whole valve anddiaphragm system operate nicely in equilibrium when the effectivediaphragm area is equal to the horizontal area of valve 52.-

Whenever during the operation of the motor it is throttled down to lowspeed or idling, valve 52 lowers until it'again comes in contact withthe diaphragm and comes again under diaphragmcontrol. With the motorwarmed up screw 56 may be adjusted to adjust the idling mixture for theengine, and when this adjustment is made valve 52 will then stand incoring' at any time in the carburetor air intake,

and thus compensates the diaphragm action, just as balance port 2|compensates for the regula-' tor and economizer action, for any changein the intake pressure due to air resistance that may be caused by aheater or cleaner, or the like; p

It will be understood that in referring to at 75 mosphericandsub-atmospheric pressures-in the that the carburetor is being fedwith air at at- 'mospheric pressure. If the air feed is at a differentpressure, say a higher pressure, then the gas pressure at the carburetorwill be correspondingly different, but always below the air pressure.The term atmospheric may thus be taken as meaning whatever air pressurethe carburetor-is operating under. It is the relative difference inthese pressures that concerns that part of the invention which causeslowering of pressure in the carburetor. The economizer arrangement,however, is operative regardless of whether the gas 'feed to thecarburetor is at a pressure less-than that of the air feed, although inpractice the gas feed pressure may always be less. I s

I claim:

1. A gas carburetor system for engines, embodying a carburetor having asuction passage with a suction outlet-and an air inlet and a throttle inthe passage, means including a pressure regulator for feeding gaseousfuel to the passage at a point at the inlet side of the throttle and ata pressure less than that in the air inlet, a valvular obstruction inthe suction passage tending normally to close the passage and capable ofopening movement'by the air current flowing through thesuction passage,a diaphragm on the upper face of which the valvular obstruc- .tionrests, and gas pressure communication between the lower face of thediaphragm and the fuel feed.

-2. A gas carburetor system forengines, embodying a carburetor having asuction passage with a suction outlet and an air inlet and a throttleand a venturi in the passage, the throttle being toward the outlet fromthe venturi, means for feeding gaseous fuel to -the Venturi throat at apressure less than that in the air inlet, a valvular obstruction in thesuction passage at the inlet side of the venturi, tending normally toclose the passage and capable of opening movement by the air currentflowing through the suction passage, a diaphragm on the upper face ofwhich the valvular obstruction rests, and a gas pressure communicationbetween the lower face of the diaphragm and the fuel feed.

3. A gas carburetor system for engines, embodying a carburetor having asuction' passage with a suction outlet and an air inlet and a throttleand a venturi in the passage, the throttle being toward the outlet fromthe venturi, means for feeding gaseous fuel to the Venturi. throat. at apressure less than that in the air inlet, the suction passage havingtherein an enlarge ment at the inlet side of the venturi, with a valveseat at the inlet end of the enlargement, a floating air valve adaptedto seat upon said seat and adapted to be raised into the passageenlargement by the air stream flowing through the suction passage, adiaphragm 'on which the air valve rests when in closed position, achamberat the upper side of said diaphragm communicating with air in theair inlet, and a chambar at the lower side of said diaphragmcommunicating with the fuel feed for transmitting the pressure of thefuel feed to the lower side of said diaphragm, and adjustable means forbalancing the valve and diaphragm.

4. A gas carburetor system for engines, embodying a carburetor having asuction passage with a suction outlet and an air inlet. and a throttlein the passage, pressure regulator means for feeding gaseous fuel to thesuction passage at apoint at foregoing specific descriptions, I haveassumedthe inlet side of the throttle and at a regulated pressure lessthan that existent in the air inlet, means in the suction passage at theinlet side of the point of fuel feed acting to reduce the air pressurein the suction passage to a point below that of fuel delivery, saidregulator including a pressure regulating valve, an actuating diaphragmand a reference pressure chamber at one side of the diaphragm, and meansto transmit to said 10 reference pressure chamber the air pressureexistent in the air inlet of the suction passage.

' 5. A gas carburetor system for engines, em-

bodying a carburetor having a' suction passage witha suction outlet andan air inlet and a throt- 15 tie in the passage, pressure regulatormeans for feeding gaseous fuel to the suction passage at a point at theinlet side of the throttle and at a regulated pressure less than thatexistent in the air inlet, means in the suction passage at the 20 inletside of the point of fuel feed acting to rehe the air pressure in thesuction passage to a int below that of fuel delivery, said regulatorincluding a pressure regulating valve, an actuating diaphragm and areference pressure chamber one side of the diaphragm, means to transmitso said reference pressure chamber the air pressure existent in the airinlet of the suction passage, and means for modifying that pressure'bysuction from the suction passage. so 6. A gm carburetor system forengines, embodyin; a carburetor having a suction passage with a suctionoutlet and an air inlet and a throttle in the passage, pressureregulator means for feeding gaseous fuel to the suction passage at a ti?point at the inlet side of the throttle and at a regulated pressure lessthan that existent in the air inlet, means in the suction passage at theinlet side of the point of fuel feed acting to reduce the air pressurein the suction passage to 4,9 a point below that of fuel delivery, saidregulator including a pressure regulating valve, an actuating diaphragmand a reference pressure cham- I ber at one side of the diaphragm, apressure transmitting passage extending between the suctier: passageinlet and said reference pressure chamber, and a branch passage fromsaid pressure transmitting passage communicating with the suctionpassage to apply suction to the pressure transmitting passage.

7. A gas carburetor system for engines, em-

cocsing a carburetor having a suction passage with a suction outlet andan air inlet and a throttie in the passage, pressure regulator means forfeeding gaseous fuel to the suction passage at a 55 point at the inletside of the throttle and at a regaciaed pressure less than that existentin the air inlet, means in the suction passage at the inlet side of thepoint of fuel feed acting to reduce the airpressure in the suctionpassage to as a point below that of fuel delivery, said regulatorincluding a pressure regulating valve, an actuatdiaphragm and areference pressure chamher at one side of the diaphragm, and a pressurecommunicating passage extending between the suction passage and thereference pressure chamer to apply suction to said chamber.

a. A gas carburetor system for engines, embodying a carburetor having asuction passage .with a suction outlet and an air inlet and a throt- 70tie in the passage, pressure regulator means for feeding gaseous fuel tothe suction passage at a point at the inlet side of the throttle and 'ata regulated pressure less than that existent in the air inlet, means inthe suction passage at the 75 inlet side of the point of fuel feedacting to reduce the air pressure in the suction passage to a pointbelow that of fuel delivery, said regulator including a pressureregulating valve, an actuating diaphragm and a reference pressurechamber at one side of the diaphragm, a pressure com- 5 municatingpassage extending between the reference pressure chamber and the suctionpassage at a point therein on the inlet side of the throttle, andvalvular means actuated by throttle movement to control said passage.

9. In a gas carbureting system for engines, a carburetor having asuction passage with a suction outlet and an air inlet and a throttlevalve in the passage, pressure controlling means for feeding gaseousfuel to the suction passage, and means for controllably varying thepressure upon the fuel feed to the suction passage; said means includinga passage communicating with the suction passage at a point' at the airinlet side of the throttle and communicating with the fuel pressurecontrolling means to apply pressure thereto, a spring seated valve insaid communicating passage and adapted to open the passage upon the'application of apredetermined amount of suction thereto from the suctionpassage, and a controlling valve in said communication passage adaptedto be actuated by throttle movement to close said passage as thethrottle approaches open position. 1

10. In a gas carbureting system for engines, a carburetorhaving asuction passage with a suction outlet and an air inlet and a throttlevalve in the passage, pressure controlled means for feeding gaseous fuelto the suction passage at a controlled pressure less than the airpressure existent in the air inlet, means in the suction passage at theinlet side of the point of fuel feed acting to reduce the air pressurein the suction passage to a pressure below that of the fuel feed, meansfor controllably varying the pressure upon thefuel 40 feed to thesuction passage, said means including a passage communicating with thesuction passage at a point at the air inlet side of the throttle andcommunicating with the fuel pressure controlling means to apply suctionthereto, and a valve in said passage adapted to open when apredetermined amount of suction is applied thereto from the suctionpassage.

-11. In a gas carburetor for,engines, a body having vertically extendingsuction passage therethrough with an upper suction outlet and a lowerair inlet and with a throttle valve and a venturi in the passage, thethrottle valve being toward the outlet from the venturi, a fuel feedpassage leading to the Venturi throat, an enlargement in the 5 suctionpassage below the venturi and a valve seat at the base of saidenlargement, a vertically movingair valve adapted to seat on said valveseat and to float on the air stream passing through the suction passage,'a valve controlling diaphragm mounted in the body below the air valveand'having diaphragm chambers above and below the diaphragm, the upperdiaphragm chamber communicating with the air inlet, an adjustablesupporting spring beneath the diaphragm, andcom- 5 munication betweenthe lower diaphragm chamber and the fuel feed.

12. In a gas carburetor for engines, a body having vertically extendingsuction passage therethrough with an upper suction outlet and a lowermoving air valve adapted to seat on said valve seat and to float ontheair stream passing through the suction passage; ax diaphragm mountedin the body below the air valve and on which diaphragm the air valvefreely rests, and said diaphragm having a limited upward movement lessthan the upward movement of the air valve, a chamber in the body abovethe diaphragm and in communication with the air inlet, a chamber in thebody below the diaphragm and in communication with the fuel feed, andanadjustable supporting springbelow the diaphragm tending to support thediaphragm and valve.

13. A gas carburetor system, embodying a carburetor having a suctionpassage with a suction outlet and an air inlet and a throttle in thepassage, means for feeding fuel to the passage at a point at the inletside of the throttle and at a pressure less than that in the air inlet,a valvular obstruction in the suction passage at the'air inlet side ofthe point of fuel feed tending normally to close the passage and capableof opening movement by the air current flowing through the suctionpassage, and means, independent of the air current movement of theobstruction,whereby the pressure existent atthe fuel feed tends to movethe obstruction in opening movement direction.

14. A gas carburetor system, embodying a carburetor having a suctionpassage with a suction outlet and an air inlet and a throttle in thepassage. means for feeding fuel to the passage at a point at the inletside of the throttle and at a pressure less than that in the air inlet,a valvular choke means positioned in the suction passage at the airinlet side of the point of fuel feed, said valvular choke means adaptedto be opened by decrease 'of pressure in the suction passage betweensaid choke means and the throttle, and

means, acting independently of said last mentioned choke openingactuated by the pressure of the fuel at the point of fuel feed andtending to open said choke means witha force which is a function of thefuel feed pressure.

15. In a gas carbureting system for engines, a

- carburetor having a suction passage with a suction outlet and an airinlet' and a throttle valve in the passage, pressure controlled meansfor feeding gaseous fuel to the suction passage, and means forcontrollably varying the pressure upon the fuel feed to the suctionpassage, said means including a passage communicating with the fuelpressure controlling means to apply thereto a pressure substantiallyequal to that existent at the air inlet, and including also a passagecommunicating with the suction passage. at a point at the air inlet sideof theithrottle and communicating with the fuel pressure controllingmeans to apply suction thereto, and a controlling valve in said lastmentioned communication passage adapted to be actuated by throttlemovement to close said passage as'the throttle approaches open position.so

ROY I". ENBIGN.

